Long-term exercise adherence refers to an individual's free choice to continue to exercise at the recommended levels. Adherence to exercise recommendations will be measured as exercise levels achieved at home or in the community at week 52 (numerator) divided by recommended amounts (denominator). Exercise levels achieved will be estimated from a 7-day activity record completed by the patient and coded for intensity using the Compendium for Physical Activities. The energy expended in activities corresponding to (or exceeding) the patient's target intensity level will be computed and will form the numerator. The recommended amounts of exercise will be calculated for each patient as the energy expended during the last week of PR. Exercise adherence will be measured at week 52 only, but subjects will be asked to complete the 7-day activity record at week 0 and week 12 to familiarize themselves with the procedure.